/**
*      author: Y_Yao
*      created: 2024-11-30 19:44:33
**/

#include<bits/stdc++.h>

using namespace std;
using LL = long long;
const LL LLINF = 1e18;
const int INF = 0x3f3f3f3f;
int n,d;

void solve()
{
    cin >> n >> d;
    string s;
    cin >> s;
    int count = 0;
    for(int i = 0;i < s.size();i++)
    {
        if(s[i] == '.') count++;
    }

    cout << count + d << endl;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);

    int t = 1;
    //cin >> t;
    while(t--)
    {
        solve();
    }
    return 0;
}